Microsoft Is Retiring Exchange Web Services

Microsoft Is Retiring Exchange Web Services: What Businesses Need to Know Before October 2026

If your organization uses Microsoft 365, an important technical change is approaching that may affect applications connected to your email, calendars, contacts, and other Exchange Online information.

Microsoft is retiring Exchange Web Services, commonly known as EWS.

Beginning in October 2026, Microsoft will start disabling EWS across Exchange Online environments. The retirement will happen in phases, with EWS scheduled to be fully disabled by April 2027.

For most employees, this change will be invisible. Outlook is not going away, Microsoft 365 email will continue working, and there is no reason to panic.

The applications connected to Microsoft 365 behind the scenes, however, deserve attention now.

What Is Exchange Web Services?

Exchange Web Services is a technology Microsoft introduced nearly two decades ago that allows software applications to communicate with Microsoft Exchange.

In simple terms, EWS is one of the ways another application can talk to your Microsoft 365 mailbox.

An application using EWS might retrieve email messages, access calendar information, synchronize contacts, work with meetings, or move information between Exchange and another business application.

For years, that made EWS an important connection point between Exchange and other software.

A CRM system, for example, might synchronize contact information with Exchange. A business application might read a shared mailbox. Scheduling software could interact with employee calendars. Custom applications developed years ago may also use EWS without the people using those applications even realizing it.

That is why the upcoming change matters.

What Is Microsoft Changing?

Microsoft stopped adding new functionality to EWS several years ago and has been encouraging developers to move applications to Microsoft Graph, its newer platform for accessing Microsoft 365 information.

The timeline is now entering its final stage.

The important takeaway is simple: organizations should identify applications still using EWS and begin addressing those dependencies now rather than waiting until the final shutdown.

This Does Not Affect On-Premises Exchange Server

One important distinction is worth emphasizing.

The EWS retirement applies to Microsoft 365 and Exchange Online.

It does not apply to on-premises Exchange Server environments.

If your organization uses Microsoft 365 for email, however, applications connected to Exchange Online should be reviewed.

Why Is Microsoft Retiring EWS?

EWS has been around for almost 20 years.

Microsoft is moving toward newer technologies that better support current requirements for security, scale, reliability, and future Microsoft 365 capabilities.

Microsoft Graph is now the recommended platform for applications that need to access Microsoft 365 information.

This does not mean EWS is suddenly unsafe today.

It means Microsoft is moving its cloud services toward newer technologies that are better suited to where Microsoft 365 is heading.

What Types of Applications Should Businesses Be Thinking About?

The challenge is that employees may not know which applications are using EWS.

Some applications have been connected to Microsoft 365 for years and simply continue running in the background.

Potential areas worth reviewing include:

• CRM and customer-management integrations
• Calendar and scheduling applications
• Applications that synchronize email or contacts
• Archiving and mailbox-management software
• Backup or migration tools
• Business applications that work with shared mailboxes
• Older Microsoft 365 integrations
• Custom applications or scripts developed internally
• Third-party applications that read or update Exchange mailbox information

This does not mean every application in these categories uses EWS.

Many modern applications already use Microsoft Graph or another supported integration method.

The important step is finding out which ones still depend on EWS.

Microsoft Has Made That Easier

Microsoft now provides an EWS Usage Report in the Microsoft 365 admin center specifically to help organizations identify applications that are still communicating with Exchange Online through EWS.

The report can show active applications, their application IDs, the EWS actions they are using, their call volume, and the date of their most recent activity.

That is much better than trying to guess which applications might be affected.

Once an application is identified, the next question becomes straightforward:

Does the vendor have an updated version or migration plan that replaces EWS?

In many cases, the answer will already be yes.

What Organizations Should Be Doing Now

This should be treated as a planning exercise rather than an emergency.

A sensible review includes:

• identifying active EWS applications
• determining which software or vendor owns those connections
• confirming whether newer versions are available
• reviewing migration guidance
• testing replacement integrations
• planning changes before Microsoft reaches the final retirement date

The objective is simple: find dependencies while there is still plenty of time to deal with them.

What Your Organization Can Do

Think about applications that interact with Microsoft 365 but may not immediately seem like email applications.

For example:

• Does a business system automatically process messages from a mailbox?
• Does a scheduling platform read employee calendars?
• Does a CRM synchronize with Outlook?
• Does a line-of-business application use shared mailboxes?
• Was a custom integration developed several years ago?

If the answer is yes, make sure those applications are included in the review.

It is much easier to investigate an application now than to discover the dependency when an integration suddenly stops working.

What You Do Not Need to Do

You do not need to start replacing applications simply because Microsoft is retiring EWS.

You also do not need to assume that every application connected to Microsoft 365 is affected.

And October 2026 is not a date when everyone’s Microsoft 365 email suddenly stops working.

This is a transition affecting a specific method that applications use to access Exchange Online.

The Best Time to Check Is Before Something Breaks

Technology changes like this are easiest to manage when they are addressed before the deadline.

EWS has performed an important role in the Microsoft ecosystem for many years, but Microsoft is clearly moving Exchange Online integrations toward Microsoft Graph and other modern technologies.

For businesses, the takeaway is straightforward:

Know which applications are connected to Microsoft 365, identify any that still rely on EWS, and make sure there is a migration path before Microsoft completes the retirement in April 2027.

The best outcome is that this change happens quietly in the background, with applications updated and migrated before users ever notice a problem.

That is exactly what proactive IT planning is supposed to accomplish.